What is the difference between work done by a gas and work done on a gas?

Question

Sir Yahya · Accepted Answer

Questions I read:
1. How is work done by a gas on a gas?

Group 1 - Work Done by/on a Gas - covers Q1
Answer:
*   **Work done BY a gas:** When a gas expands, it pushes against its surroundings (like a piston) and transfers energy to them. This is called work done *by* the gas. In thermodynamics, this work is usually considered positive.
*   **Work done ON a gas:** When the surroundings (like a piston) compress a gas, they transfer energy to the gas. This is called work done *on* the gas. This work is usually considered negative in thermodynamics.
*   In simple terms, work is done when there is a change in volume against an external pressure.

Also suits: What is the difference between work done by a gas and work done on a gas?
Memory tip: "By" means gas gives energy (expands), "On" means gas receives energy (compresses).